Hes honest about saying that he's tempted, after all everyone likes an improved wage. But which club there would honestly be an alternative to Bayern? If he wants to, then he can get an improved contract at Bayern that would match his interests. Bayern doesnt pay everyone ridiculous wages, but Müller would be one of the few exceptions where they wouldnt even hesitate.
But I dont think that he would leave over money-issues anyway. The guy is tempted by wages, like everyone in this world, but he never looked incredibly money-drven like some others that jump into my mind. Certainly wouldnt base a decision like that just on the moneyfactor.